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Irrigation Winterization

November 12, 2009

 

If you haven’t already done so, the ritual of irrigation blow out is certainly on everyone’s mind this time of year. This procedure signifies the end of another growing season along with the realization that winter and the accompanying freezing temperatures are probably right around the corner. Properly blowing out an irrigation system ensures that minimal damage will occur during the winter months. Although blow out is a yearly occurrence, there doesn’t seem to be a great deal of literature available about this important procedure. There seems to be various philosophies and most learn from field experience.

One aspect of blow out that has changed over the years is the pressure which the system is blown out. One reason for this change is the fact that sprinkler heads are now primarily comprised of plastic componts compared to their steel predecesors. As a result, the pressure which the system is blown out has been reduced. One way to help reduce the pressure is by using a pressure regulator.

The pressure regulator is usually mounted just off the compressor. The pressure can be monitored and adjusted by a handle on top of the regulator. I have often heard that 50 psi is sufficient to blow out most systems. Obviously, the higher the pressure, the greater the chance of causing damage to the piping system and the sprinkler heads. The other consequence of using higher pressures is coupled to the pressure of the compressor.

Compressors also have a pressure gauge and increasing the pressure of the regulator will decrease the pressure inside the compressor and vice verca. Most compressors should not be operated under 80 psi. Under 80 psi, oil can blow past the seals in the compressor and enter the piping system. Of course you won’t realize this has happened until you charge the system in the spring and oil comes spewing out of sprinkler heads.

Let me know if you have any tips from the field concerning winterization of irrigation systems. Hope everyone has a safe and successful blowout.
 

Marcus Jones

Graduate Research Assistant

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It’s Beginning to Look a Lot Like Christmas

November 13, 2011

Many parts of the state received their first snowfall last week. The days are shorter and 4” soil temperatures are slipping from the low 40’s into the high 30’s. Most trees have lost the majority of their leaves. Long-establishing creeping bentgrass greens display a spectrum of purple patches. Everywhere you look, there are signs that another growing season is coming to an end. But irrigation winterization may best signify that the growing season is over and winter is just around the corner.

Irrigation winterization is the process of evacuating water from the irrigation pipes to avoid damage from freezing temperatures. While a portion of the water can be evacuated at dead ends and low points of the piping through manual and automatic drain valves, larger irrigation systems also “blowout” the piping system using compressed air. This method of winterization can be very damaging to the piping system and dangerous to workers if proper safety procedures are not followed.

I was reminded of the hazards that can occur during the winterization procedure when I received the picture below from a former student. In this scenario an individual head would not activate from the satellite box and the employee went to flag on the head. When the head activated, the internal assembly broke free from the bucket striking the worker under the chin.
 

Irrigation winterization can be dangerous and safety precautions need to be taken to avoid injury.

This post will outline some of the basic safety measures that should be followed to avoid personal injury and undue stress on the irrigation system.

Use a safety harness to tether the air hose to the compressor. Air hoses connect to the compressor though a claw or similar type coupling. The connection is usually secured with cotter pins or wire but also consider using a safety harness. The harness will prevent the hose from flailing about in the event the connection fails while under pressure.

 

A harness that connects the air hose to the compressor provides additional safety in case the connection fails when under pressure.

Do not force air through the backflow preventer. Be sure to hookup after the backflow preventer as forcing air through this component can cause damage. First, blowout the system, then allow the backflow preventer to drain.

Regulate the air pressure with a pressure regulator. Even though larger irrigation system may operate with water pressures in excess of 100 psi, air pressures of this magnitude can damage the system. Use of a pressure regulating valve can help prevent over-pressurization. Most manufacturers recommend air pressures around 50 psi.

A pressure regulator can help prevent excessively high pressures from damaging valves, pipes, and irrigation heads.

Do not stand directly over irrigation components when under pressure. Air is less viscous compared to water and can generate greater stress under comparable pressures. Weak points in the irrigation system can fail under air pressure. Protect yourself from personal injury by staying clear of irrigation components when under pressure. It’s also a good idea to wear proper eye and ear protection during the winterization process.

Do not work on a sprinkler head while under pressure. If a head sticks on or won’t activate automatically or manually valve the section off and bleed the pressure through a quick coupler. Once the air stops at the quick coupler the head is safe to work on.

Evacuate water ahead of time. Before activating individual sprinkler heads use drain valves and quick couplers to initially evacuate water. This will reduce the amount of water in the system and can shorten the time needed to evacuate air through sprinkler heads. Less air moving through valves and sprinkler components and will help cut down on wear and tear.

Quick couplers and manual drain valves can be used to drain water before evacuating water through sprinkler heads.

Do not allow sprinkler heads to run for prolonged periods of time. Sprinkler drive mechanisms are normally lubricated as the water moves through the internal assembly. In the absence of water, heat caused from friction can damage these plastic components. Cycle between one or more stations to avoid excess buildup of heat.

Taking care to follow these safety procedures can help the winterization process go smoothly while minimizing damage to the irrigation system and preventing personal injury.

Hoping you have successful (and safe) winterizations!

Marcus Jones
Assistant Scientist

 

 

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